1.13 An Arrow GUI: "arrow-gui.ss"
The teachpack provides operations for creating and manipulating an arrow GUI. We recommend using the world teachpack instead.
modelT (-> button% event% true)
A modelT is a function that accepts and ignores two arguments.
Reads out the current state of the message
field.
Displays s in the
message field.
Connects four
controllers with the four directions in the arrow window.
Example:
| ; Advanced |
| (define (make-model dir) |
| (lambda (b e) |
| (begin |
| (view dir) |
| (printf "~a ~n" (control))))) |
| (connect |
| (make-model "left") |
| (make-model "right") |
| (make-model "up") |
| (make-model "down")) |
Now click on the four arrows. The message field contains the current
direction, the print-out the prior contents of the message field.